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#! /usr/bin/env perl
# Generate C definitions for parsing Matroska files.
use strict;
use warnings;
use FindBin;
use lib "$FindBin::Bin/lib";
use Parse::Matroska::Definitions;
use Parse::Matroska::Reader;
use Getopt::Long;
use List::Util qw{max};
my @global_elem_list = @Parse::Matroska::Definitions::global_elem_list;
Getopt::Long::Configure(qw{auto_version auto_help});
my %opt;
GetOptions(\%opt,
"generate-header",
"generate-definitions",
"full",
);
if ($opt{"generate-header"}) {
generate_c_header();
} elsif ($opt{"generate-definitions"}) {
generate_c_definitions();
} else {
for (@ARGV) {
my $reader = Parse::Matroska::Reader->new($_ eq '-' ? \*STDIN : $_) or die $!;
while (my $elem = $reader->read_element($_ eq '-')) {
process_elem($elem, $_ eq '-');
}
}
}
# Generate declarations for libmpdemux/ebml_types.h
sub generate_c_header {
print "/* Generated by TOOLS/matroska.pl, do not edit manually */\n\n";
# Write a #define for the ElementID of each known element
for my $el (@global_elem_list) {
printf "#define %-40s 0x%s\n", $el->{definename}, $el->{elid};
}
print "\n";
# Define a struct for each ElementID that has child elements
for my $el (@global_elem_list) {
next unless $el->{subelements};
print "\nstruct $el->{structname} {\n";
# Figure out the length of the longest variable name
# Used for pretty-printing in the next step
my $l = max(map { length $_->{valname} } values %{$el->{subelements}});
# Output each variable, with pointers for array (multiple) elements
for my $subel (values %{$el->{subelements}}) {
printf " %-${l}s %s%s;\n",
$subel->{valname}, $subel->{multiple}?'*':' ', $subel->{fieldname};
}
print "\n";
# Output a counter variable for each element
# (presence/absence for scalars, item count for arrays)
for my $subel (values %{$el->{subelements}}) {
print " int n_$subel->{fieldname};\n"
}
print "};\n";
}
print "\n";
# Output extern references for ebml_elem_desc structs for each of the elements
# These are defined by generate_c_definitions
for my $el (@global_elem_list) {
next unless $el->{subelements};
print "extern const struct ebml_elem_desc $el->{structname}_desc;\n";
}
print "\n";
# Output the max number of sub-elements a known element might have
printf "#define MAX_EBML_SUBELEMENTS %d\n",
max(map { scalar keys %{$_->{subelements}} }
grep { $_->{subelements} } @global_elem_list);
}
# Generate definitions for libmpdemux/ebml_defs.c
sub generate_c_definitions {
print "/* Generated by TOOLS/matroska.pl, do not edit manually */\n\n";
# ebml_defs.c uses macros declared in ebml.c
for my $el (@global_elem_list) {
print "\n";
if ($el->{subelements}) {
# set N for the next macros
print "#define N $el->{fieldname}\n";
# define a struct ebml_$N_desc and gets ready to define fields
# this secretly opens two scopes; hence the }}; at the end
print "E_S(\"$el->{name}\", ".scalar(keys %{$el->{subelements}}).")\n";
# define a field for each subelement
# also does lots of macro magic, but doesn't open a scope
for my $subel (values %{$el->{subelements}}) {
print "F($subel->{definename}, $subel->{fieldname}, ".
($subel->{multiple}?'1':'0').")\n";
}
# close the struct
print "}};\n";
# unset N since we've used it
print "#undef N\n";
} else {
print "E(\"$el->{name}\", $el->{fieldname}, $el->{ebmltype})\n";
}
}
}
sub repr {
my @ret;
foreach (@_) {
if (/'/) {
s/"/\\"/g;
push @ret, "\"$_\"";
} else {
push @ret, "'$_'";
}
}
return @ret if wantarray;
return pop @ret if defined wantarray;
return;
}
sub process_elem {
my ($elem, $read_bin) = @_;
unless ($opt{full}) {
if ($elem->{name} eq 'Cluster' || $elem->{name} eq 'Cues') {
$elem->skip;
return;
}
}
die unless $elem;
if ($elem->{type} ne 'skip') {
print "$elem->{depth} $elem->{elid} $elem->{name} size: $elem->{content_len} value: ";
}
if ($elem->{type} eq 'sub') {
print "subelements:\n";
while (my $chld = $elem->next_child($read_bin)) {
process_elem($chld);
}
} elsif ($elem->{type} eq 'binary') {
my $t = "<skipped $elem->{content_len} bytes>";
if ($elem->{content_len} < 20) {
$t = unpack "H*", $elem->get_value;
}
print "binary $t\n";
delete $elem->{value};
} elsif ($elem->{type} eq 'ebml_id') {
print "binary $elem->{value}->{elid} (".($elem->{value}->{name}||"UNKNOWN").")\n";
} elsif ($elem->{type} eq 'skip') {
# skip
} elsif ($elem->{type} eq 'str') {
print "string ". repr($elem->get_value) . "\n";
} else {
print "$elem->{type} ". $elem->get_value ."\n";
}
}
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